Immune checkpoints are regulatory pathways in the immune system that maintain self-tolerance and modulate the duration and amplitude of physiological immune responses in peripheral tissues. They are crucial for preventing autoimmunity and protecting tissues from damage when the immune system is responding to infections. Key immune checkpoint proteins include CTLA-4 (Cytotoxic T-Lymphocyte Associated Protein 4) and PD-1 (Programmed Death-1), along with their ligands such as PD-L1 (Programmed Death-Ligand 1).
